Federal, state and local authorities in 40 cities also arrested 884 people, including 99 suspected pimps, on a variety of charges.
The children were found during Operation Cross Country V, a three-day roundup targeting child traffickers and pimps that is part of the FBI's Innocence Lost National Initiative.
FBI: Operation Cross Country V
"Child prostitution continues to be a significant problem in our country, as evidenced by the number of children rescued through the continued efforts of our crimes against children task forces," said Shawn Henry, executive assistant director of the FBI's Criminal, Cyber, Response, and Services Branch.
The FBI is working with the National Center for Missing and Exploited Children to identify the children.
The child victims are removed from prostitution; the adults face a variety of state and local charges.
Since its inception seven years ago, groups working under the Innocence Lost National Initiative have rescued more than 1,200 children; 625 pimps, madams, and associates have been convicted of exploiting children through prostitution.